POS0247 RESOLUTION OF ENTHESITIS AND PERIPHERAL ARTHRITIS WITH BIMEKIZUMAB IN PATIENTS WITH AXIAL SPODYLOARTHRITIS: WEEK 52 RESULTS FROM THE BE MOBILE 1 AND BE MOBILE 2 PHASE 3 STUDIES
Authors: S. Ramiro, D. Poddubnyy, P. J. Mease, C. López-Medina, C. Fleurinck, M. Kim, U. Massow, V. Taieb, T. W. Kragstrup, D. Mcgonagle
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> A history of enthesitis or peripheral arthritis has been reported in &gt;30% of patients (pts) with axial spondyloarthritis (axSpA),<sup>[1]</sup> both of which contribute to disease burden. Bimekizumab (BKZ), a monoclonal IgG1 antibody that selectively inhibits interleukin (IL)-17F in addition to IL-17A, has demonstrated efficacy in phase 3 parallel studies in pts with non-radiographic (nr-)axSpA (BE MOBILE 1) and radiographic axSpA (r-axSpA i.e. ankylosing spondylitis; BE MOBILE 2).<sup>[2,3]</sup> <h3>Objectives</h3> To evaluate the impact of BKZ on the main peripheral manifestations of axSpA, to Week (Wk) 52. <h3>Methods</h3> Pts in BE MOBILE 1 (NCT03928704; nr-axSpA) met Assessment of SpondyloArthritis International Society (ASAS) classification criteria, pts in BE MOBILE 2 (NCT03928743; r-axSpA) met both modified New York and ASAS criteria. Pts were randomised to receive subcutaneous BKZ 160 mg every 4 wks (Q4W) or placebo (PBO) to Wk 16. From Wk 16 all pts received BKZ 160 mg Q4W.<sup>[2]</sup> Among pts with enthesitis (Maastricht Ankylosing Spondylitis Enthesitis [MASES]&gt;0), at least one swollen joint (SJC&gt;0), or at least one tender joint (TJC&gt;0) at baseline (BL), we report mean change from baseline (CfB) using multiple imputation (MI). Pts (%) achieving complete resolution of enthesitis (MASES=0 in pts with MASES &gt;0 at BL) and peripheral arthritis (SJC=0 in pts with SJC &gt;0 at BL, assessed in 44 joints) using non-responder imputation, is also reported. <h3>Results</h3> At BL, 73.2% nr-axSpA pts (BKZ: 94/128, PBO: 92/126) and 59.9% r-axSpA pts (BKZ: 132/221, PBO: 67/111) had enthesitis; peripheral arthritis (SJC &gt;0) was present in 34.6% (BKZ: 45/128, PBO: 43/126) and 19.9% (BKZ: 44/221, PBO: 22/111) of nr-axSpA and r-axSpA pts, respectively. BL MASES, SJC and TJC were largely similar between treatment arms (<b>Table 1</b>). Across the axSpA spectrum, greater mean CfB in MASES was achieved with BKZ vs PBO at Wk 16; improvements continued to Wk 52 with continuous BKZ and in pts switching from PBO to BKZ at Wk 16 (<b>Table 1</b>). Similarly, &gt;50% BKZ pts achieved complete resolution of enthesitis at Wk 16 vs &lt;33% of PBO pts; by Wk 52, responses of PBO/BKZ-switchers approached those of BKZ pts (<b>Figure 1</b>). At Wk 16, greater mean CfB in SJC and TJC was achieved with BKZ vs PBO-randomised pts with nr-axSpA. Improvements largely continued to Wk 52 with BKZ for both continuous BKZ and PBO/BKZ-switcher pts (<b>Table 1</b>). Resolution of peripheral arthritis was achieved by &gt;57% of BKZ vs &gt;41% of PBO-randomised pts at Wk 16; by Wk 52, proportions were similar among continuous BKZ and PBO/BKZ-switcher pts (<b>Figure 1</b>). <h3>Conclusion</h3> BKZ treatment resulted in sustained improvements in peripheral manifestations across the axSpA spectrum. Resolution of enthesitis was achieved in ~half of BKZ-treated pts by Wk 52; a similar pattern was observed for peripheral arthritis, with more than half of pts achieving resolution to Wk 52. <h3>References</h3> [1]López-Medina C. RMD Open 2021;7(1):e001450; [2]Baraliakos X. Arthritis Rheumatol 2022;74(suppl 9); [3]Boel A. Ann Rheum Dis 2019;78:1545–9. <h3>Acknowledgements:</h3> This study was funded by UCB Pharma. Medical writing support was provided by Costello Medical, funded by UCB Pharma. <h3>Disclosure of Interests</h3> Sofia Ramiro Consultant of: AbbVie, Eli Lilly, Novartis, Pfizer, Sanofi and UCB Pharma, Grant/research support from: AbbVie, Galapagos, MSD, Novartis, Pfizer and UCB Pharma, Denis Poddubnyy Speakers bureau: AbbVie, Bristol-Myers Squibb, Eli Lilly, MSD, Novartis, Pfizer and UCB Pharma, Consultant of: AbbVie, Biocad, Eli Lilly, Gilead, GSK, MSD, Moonlake, Novartis, Pfizer, Samsung Bioepis and UCB Pharma, Grant/research support from: AbbVie, Eli Lilly, MSD, Novartis and Pfizer, Philip J Mease Speakers bureau: AbbVie, Amgen, Eli Lilly, Janssen, Novartis, Pfizer and UCB Pharma, Consultant of: AbbVie, Acelyrin, Aclaris, Amgen, Bristol-Myers Squibb, Boehringer Ingelheim, Eli Lilly, Galapagos, Gilead, GSK, Janssen, MoonLake Pharma, Novartis, Pfizer, Sun Pharma and UCB Pharma, Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, Eli Lilly, Gilead, Janssen, Novartis, Pfizer, Sun Pharma and UCB Pharma, Clementina López-Medina Speakers bureau: AbbVie, Eli Lilly, Janssen, MSD, Novartis, and UCB Pharma, Consultant of: Eli Lilly, Novartis and UCB Pharma, Grant/research support from: AbbVie, Eli Lilly, Novartis and UCB Pharma, Carmen Fleurinck Employee of: Employee of UCB Pharma, Mindy Kim Employee of: Employee of UCB Pharma, Ute Massow Employee of: Employee of UCB Pharma, Vanessa Taieb Employee of: Employee of UCB Pharma, Tue Wenzel Kragstrup Speakers bureau: AbbVie, Bristol-Myers Squibb, Eli Lilly, Novartis, Pfizer and UCB Pharma, Consultant of: Bristol-Myers Squibb, Eli Lilly, Gilead and UCB Pharma, Grant/research support from: Gilead, Dennis McGonagle Speakers bureau: AbbVie, Celgene, Janssen, Merck, Novartis, Pfizer and UCB Pharma, Consultant of: AbbVie, Celgene, Janssen, Merck, Novartis, Pfizer and UCB Pharma, Grant/research support from: AbbVie, Celgene, Janssen, Merck, Novartis and Pfizer.